<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script src="../../js/jquery-1.4.2.js"></script>
</head>
<body>
    <select onclick="selectCity()" id="province">
        <option>北京市</option>
        <option>河北省</option>
        <option>辽宁省</option>
        <option>山东省</option>
    </select>
    <select id="city">
        <option>--请选择城市--</option>
    </select>
</body>
    <script>
        var data={
            '北京市':['海淀区','朝阳区','丰台区'],
            '河北省':['石家庄','唐山','邯郸'],
            '辽宁省':['沈阳','大连','鞍山'],
            '山东省':['青岛','济南','烟台']
        }

    </script>
</html>